Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Mössbauer spectrometry

Zero-field and in-field Mössbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.     

Hierarchical interaction in design systems

Multilevel hierarchical schemes for complex system design are considered. Coordination of engineering-design decisions made at different levels is examined. An interactive design-seeking procedure is described.Translated from Programmno-apparatnye Sredstva i Matematicheskoe Obespechenie Vychislitel'nykh Sistem, pp. 128–135, 1994.     

Optical limiters based on liquid-crystal microlenses

The possibility of using liquid-crystal microlenses for solving the problems of optical limiting is demonstrated. A compact optical system based on these microlenses is suggested and studied; in this system, two-photon absorption in extrinsic nematic liquid crystals is used as a limiting mechanism.     

Search for CP-violation in Ko→3πo decay

Using the 180 liter ITEP liquid xenon bubble chamber the time distribution of 22 K^o → 3π^o decays has been studied. For the ratio η_ooo of amplitudes K_S → 3π^o and K_L → 3π^o decays we found Reη_ooo = ?0.04 ± 0.45 and Imη_ooo = 0.45 ± _0.65^0.50. Assuming CPT invariance we obtained |η_ooo|² < 1.2 and Γ(K_S → 3π^o)/ Γ(K_S) ? 4.3 × 10^?4 at 90% confidence level.     

Properties of finite-difference schemes for singular integrodifferential equations of index 1

Systems of integrodifferential equations with a singular matrix multiplying the highest derivative of the unknown vector function are considered. An existence theorem is formulated, and a numerical solution method is proposed. The solutions to singular systems of integrodifferential equations are unstable with respect to small perturbations in the initial data. The influence of initial perturbations on the behavior of numerical processes is analyzed. It is shown that the finite-difference schemes proposed for the systems under study are self-regularizing.     

Application of the Todd–Atherton synthetic approach for chemical modification of tetraene macrolide antibiotic lucensomycin

Lucensomycin, tetraene macrolide antibiotic, has been chemically modified with dialkyl(diaryl) phosphites under conditions of the Todd–Atherton reaction. The reaction has yielded the corresponding dialkyl-(diaryl) amidophosphate derivatives of the antibiotic. Physico-chemical properties of the prepared derivatives as well as their toxicity and antifungal activity towards a series of pathogenic Candida yeast-like fungi have been studied. The automated decision-making information system for selection of highly efficient antibiotics has been described.     

Magnetic State of Quasiordered Fe–Al Alloys Doped with Ga and B: Magnetic Phase Separation and Spin Order

Results of structural, magnetic, and Mössbauer studies of quasi ordered alloys Fe₆₅Al_{35 ? x}M _x (M _x = Ga, B; x = 0, 5 at %) are presented. The magnetic state of examined structurally–single-phase alloys at low temperatures is interpreted from the viewpoint of magnetic phase separation. An explanation is proposed for the observed behavior of magnetic characteristics of Fe₆₅Al₃₅ and Fe₆₅Al₃₀Ga₅ in the framework of the model of two magnetic phases, a ferromagnetic-type one and a spin density wave. The boron-doped alloy Fe₆₅Al₃₀B₅ is shown to demonstrate behavior that is typical of materials with the ferromagnetic type of ordering.     

Charged Particle Distribution near the Shock Front in a Glow Discharge

The charged particle distribution near the front of a shock wave propagating in the glow discharge plasma has been investigated. It has been found that the ion concentration before the front varies nonmonotonically. Behind the shock front, the charged particle concentration varies smoothly in contrast to the neutral component density.     

Mössbauer and Magnetic Study of Lanthanum Manganite La1 – xCaxMn0.98Fe0.02O3 + δ (x = 0.05, 0.10, 0.20): Nonstoichiometric and Stoichiometric Composition

Crystallography Reports - Mössbauer and magnetic study of calcium-doped lanthanum manganites La1&nbsp;–&nbsp;xCaxMn0.98Fe0.02O3&nbsp;+&nbsp;δ (x = 0.05, 0.10, 0.20)...